In Katy Perry's case, we already knew she loved the idea of being a walking flashlight. The singer garnered worldwide attention for a light-up dress she wore to a gala in May. So we weren't surprised when she took the stage wearing a glow-in-dark pink top and blue shorts (for a second it looked like her shoes lit up, too). And just when Katy was this close to making light-up garments her signature, Christina Aguilera came along and upped the ante.

Sure, Katy rocked lights all over her body, but Xtina was more selective, and only put the lights on one place ... her lady parts! And not just dotted lights either. Christina wore a light-up heart between her legs. And it BLINKED. For us, that makes Christina the winner of this glow-in-the dark face-off, simply due to the fact that if all the power ever mysteriously went out in the Gibson Amphitheater, we could simply rely on Xtina to guide us to safety with her illuminated vag.